Gas turbine having adjustable nozzle flow means



S. KOFINK June 16, 1964 3,137,477 GAS TURBINE HAVING ADJUSTABLE NOZZLE FLOW MEANS 2 Sheets-Sheet 1 Filed Oct. 24, 1961 Jhrenfar: 51E GFRIED KOFINK BY s. KOFINK 3, GAS TURBINE HAVING ADJUSTABLE NOZZLE FLOW MEANS June 16, 1964 2 Sheets-Sheet 2 Filed Oct. 24, 1961 Jnrentar: SIEGFRIED KOFINK 3,137,477 GAS TURBINE HAVING ADJUSTABLE NOZZLE FLOW MEANS Siegfried Kofinir, Zell (Neckar), Germany, assignor to GeratebawEberspacher OHG, Esslingen (Neckar), Ger

many, a German firm Filed Get. 24, 1961, Ser. No. 147,356. Claims priority, application Germany Oct. 25, 1960 2 (Ziaims. (Cl. 253-52) This invention relates in general to gas turbines and in particular to a new and useful gas turbine construction having an impulse nozzle ring with means for adjusting the flow cross sectional areas to and through the nozzles of the ring for the purposes of maintaining uniform speed during the changes of conditions in the operation of the turbine.

In the operation of gas turbines, the rotational speed of the turbine wheel will Vary in relation to the amount of gas supplied to the turbine. In those cases where the turbine is employed in connection with an air compressor or supercharger servicing an engine which furnishes the turbine gases, it is of particular importance to maintain the rotational speed of the turbine in a predetermined relationship with respectto the speed of the engine with which the supercharger is associated. Prior to the present invention, most gas turbines included throttling devices which were employed in the gas supply line or in the supply of the waste gases for such purposes. In some constructions the individual vanes of the nozzle ring are made adjustable in order to change the nozzle cross section. In still others the nozzles are a fixed design constructed for optimal operation of the expected op erating range. Both of these constructions have limitations in that they will only function completely efiiciently in narrow limits of the operational range.

Attempts have been made to broaden the operational range in which the turbine can operate efiiciently by providing the vanes which are adjustable for changing the flow cross section in addition to the flow angle. All

of the prior art devices act as throttling devices which do not provide a corresponding change in the turbine wheel and cause a divergence in the operation of the turbine wheel from optimum conditions.

In accordance with the present invention, means are provided for covering the individual nozzles of the nozzle wheel at the circumference thereof either entirely or partly. In this manner the available flow cross sectional area of the overall nozzle ring can be adjusted in a simple manner to a multitude of operational conditions.

In a preferred arrangement, individual baffles or coverings located at the circumference of the nozzle ring are associated with correspondingly dimensioned coverings in the turbine wheel or spiral. In such an arrangement,

either the nozzle rings or the coverings located in .the tin bine casing are made adjustable for movement relative to the other for controlling the flow area through the individual nozzles. In one position the covers in the turbine casing may be arranged to register with the covered nozzle portions of the nozzle ring, in which instance the flow area through the individual nozzles of the nozzle ring is the largest. rings are moved relatively, a portion of one or more of the individual nozzles is proportionately covered by the amount of such relative movement to cut off the flow area through the nozzles by the desired amount in accordance with the operational conditions. In a preferred arrangement, the covers for the nozzle ring are advantageously constructed as members defined in the turbine spiral or housing in the form of Webs which may be 3,137,477 Patented June 16', 1964 2 positioned either in alignment with a nozzle on the nozzle wheel or with a covered portion defined on such wheel. I

The invention thusmakes it possible'to obtain an adjustment for the gas flow area starting from the greatest flow cross section at high gas supply to a decreased flow cross section upondecreasing gas supply. The adjust: ment permits substantially constant speed conditions within a very large operating range which adjustment is determined so that optimum ffiow' conditions are maintained over the complete operationalrange of the turbine.

Accordingly, it is an object of the invention to provide an improved gas turbine construction.

A further object of the invention is to provide a gasturbine construction having an impulse nozzle wheel with blocked or'covered nozzle portions arranged in associationiwith the casing or turbine' spiral having coverings, the spiral and the nozzle wheel. being relatively adjustable to control the gas flow area 'to the turbine wheel. 7

A further object of the invention is to provide a gas turbine construction having a nozzle wheel with a plurality of nozzlesde'fined thereon andwith covered portions located between some of said nozzles and including i a casing or turbine spiral having bafile or coveredareas which are adapted to align either with covered nozzle areas or portions of the nozzles for the purpose of controllinggas flow to the turbine wheel.

. A further object of the invention is to provide a gas turbine-construction which is simple in design, rugged in When the coverings or the nozzle.

construction and economical to manufacture. V

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there isillustrated and described a preferred embodiment of the invention.

In the drawings: FIG. 1 is a somewhat schematic transverse section through the gastu rbine portion for a supercharger coni struct'ed in accordance with the invention;

FIG. 2 is-a viewsimilar to FIG. l 'but indicating the partsin a position adjusted from that indicated in FIG.

1 to compensate for operational conditions of gas flow. FIG. 3 is a schematic'transverse section through the longitudinal section of the turbine as shown in FIGS. 1 and 2.

Referring to the drawings in particular, the invention embodied therein includes a gas' turbine portion generally'designated 1 of a supercharger which in the embodiment indicated advantageously includes an inflow gas conduit portion 1a having two flow channels 10 and 122; defined by a wall 14 andspiral walls16 and 18.

Within the turbine casing or spiral there is a rotatably adjustable impulse turbine generally designated 2 having a plurality of vanes 20 definingnozzles 22 and circumferentiallyspaced covered areas 3a, 3b, 3c, and 3d. Gas for powering the turbineiisdirected through conduits 10 and 12 and through the nozzles 22 to the turbine wheel which is concentrically arranged in respect to the nozzles but which is not indicated for clarity of illustration purposes only.

In accordance with the invention, the covered areas 3a, 3b, 3c and 3d of the nozzle wheel 2 may be either aligned with or offset from coverings or baffles 4a,, 4b,

4c and 4d. In high gas flow conditions all of the nozzles 22 are exposed for gas flow therethrough. Means are adjustment of the nozzle wheel 2 in respect to the coverings 4a, 4b, 4c and 4d for the purpose of cutting down the flow area through the nozzles 22 when the operating conditions are such to require the handling of a lesser volume of gas in order to maintain a constant speed of the turbine wheel.

In a preferred arrangement, the nozzle wheel 2 is mounted so that it will be rotatably adjusted in respect to the baffles or covers 4a, 4b, 4c and 4d which in the embodiment indicated in FIGS. 1 and 2 are fixed elements. It should be appreciated, however, that in some instances it is preferable to make the nozzle Wheel 2 stationary and to provide a mounting for the coverings 4a, 4b, 4c and 4d within the turbine 1 which permits relative rotational adjustment thereof in respect to the turbine wheel 2.

Thus, it is apparent that the device permits the adjustment of the nozzle flow area in accordance with various operating conditions between intermediate points indicated between the uncovered full flow area condition indicated in FIG. 1 to the condition in which one nozzle of each group is completely covered as indicated in FIG. 2.

In the embodiment indicated, the nozzle wheel 2 comprises four nozzle groups of three nozzles 22 separated by the covered nozzle areas 3a, 3b, 3c and 3d. In FIG. 1 each of the covered areas 3a, 3b, 3c and 3d are aligned with corresponding coverings or baflles 4a, 4b, 4c and 4d so that the nozzles 22 are completely exposed for gas flow therethrough. In FIG. 2, on the other hand, the nozzle wheel 2 and the coverings 4a, 4b, 4c and 4d are moved relatively so that the coverings completely cover one of the nozzles 22 in each of the nozzle groups. Of course, the intermediate positions may be achieved where only a portion of one of the nozzles 22 is covered by the coverings 4a, 4b, 4c and 4d. In the FIG. 2 embodiment the nozzle flow area has been reduced from that indicated in FIG. 1 by four complete individual nozzle areas.

It should be appreciated that the relative movement between the ring 2 and the Web members 4a, 4b, 4c and 4d is carried out in accordance with the operating conditions of the device based on the gas flow which is delivered through the conduits 1t) and 12. Thus, suitable means are advantageously provided in the conduits and 12 for sensing the operating conditions making the relative adjustment between nozzle areas 3a, 3b, 3c and 3d and the webs 4a, 4b, 4c and 4d as required. In some instances this adjustment may be made manually.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

FIG. 3 is an axial section of the turbine presented in FIGS. 1 and 2 with different intermediate positions of the nozzle ring 2. The nozzle ring 2 isas shown in the above indicated figures-fixed on the bolts 24 of the leading ring 23. The bolts 24 are movable in kerves 1b of the flow gas conduit portion 1!). For tightness of the kerves 1b a tightening plate 25 is fixed on the bolts 24 in such a manner that it cannot turn. This is attained by a flattening of the bolts 24 and corresponding hollow on the tightening plate 25. By means of the compression spring 26 supported at the leading ring 23 the tightening plate 25 is pressed against the tightening plane. The

ber of revolutions of the turbine can indicate the quantity for the required adjustment of the nozzle ring 2.

When turning the nozzle ring 2, the covered areas Six/4a, 3b/4b, 3c/4c and 3d/4d in the initial position- FIG. 1lead to reciprocal displaced position (FIG. The coverings 4a-4d block thereby neighbouring located nozzle channels 22 partly or entirely. By increased blocking of the transverse section of the nozzle passage its reaction degree will remain constant in spite of the decreasing gas charge.

It is also provided to install in one and the same turbine different nozzle ring 2 with an increased quantity of covering sections 3. The coverings 4 in the turbine case are here as well as the adjustment installation unnecessary. For diflerent operation conditions only the right nozzle ring 2 has to be chosen.

What is claimed is:

1. A gas turbine comprising a casing having an outer wall defining an inlet for operating gases and a volute for delivering operating gases in an inwardly spiraling di rection, a turbine wheel rotatably mounted in said casing arranged for receiving gases directed inwardly by said casing and for discharging gases axially, an inner wall extending from said inlet into said casing and dividing the operating gas flowing into said casing and terminating in a widened area and forming a first nozzle ring cover, said outer wall having a widened area adjacent said inlet forming a second nozzle ring cover, and a nozzle ring concentrically mounted within said casing and surrounding the periphery of said turbine Wheel and including vanes defining nozzles for directing operating gases to said turbine wheel and including some areas which are covered for preventing operating gas flow therethrough, the covered areas being of a size which may be aligned with the respective ones of said first and second nozzle ring covers, said nozzle ring being movable for adjusting the alignment of said covered areas of said nozzle ring in respect to said first and second nozzle ring covers for varying the operating gas flow to said turbine wheel.

2. A gas turbine according to claim least one additional nozzle ring cover formed by an axially extending portion of said casing spaced circumferentially in respect to said nozzle ring from said first and second nozzle ring covers.

1, including at References Cited in the tile of this patent 

1. A GAS TURBINE COMPRISING A CASING HAVING AN OUTER WALL DEFINING AN INLET FOR OPERATING GASES AND A VOLUTE FOR DELIVERING OPERATING GASES IN AN INWARDLY SPIRALING DIRECTION, A TURBINE WHEEL ROTATABLY MOUNTED IN SAID CASING ARRANGED FOR RECEIVING GASES DIRECTED INWARDLY BY SAID CASING AND FOR DISCHARGING GASES AXIALLY, AN INNER WALL EXTENDING FROM SAID INLET INTO SAID CASING AND DIVIDING THE OPERATING GAS FLOWING INTO SAID CASING AND TERMINATING IN A WIDENED AREA AND FORMING A FIRST NOZZLE RING COVER, SAID OUTER WALL HAVING A WIDENED AREA ADJACENT SAID INLET FORMING A SECOND NOZZLE RING COVER, AND A NOZZLE RING CONCENTRICALLY MOUNTED WITHIN SAID CASING AND SURROUNDING THE PERIPHERY OF SAID TURBINE WHEEL AND INCLUDING VANES DEFINING NOZZLES FOR DIRECTING OPERATING GASES TO SAID TURBINE WHEEL AND INCLUDING SOME AREAS WHICH ARE COVERED FOR PREVENTING OPERATING GAS FLOW 